High blood pressure can occur in pregnancy in two forms. It may be a preexisting condition, called chronic hypertension, or it can develop during pregnancy--a condition known as gestational hypertension. It is also called toxemia or preeclampsia and occurs most often in young women with a first pregnancy.
AC relays. AC relays are manufactured similar to their DC counterparts. If AC current is applied to a DC relay, the relay will pulse at the frequency of the AC current. To overcome this problem, the core is equipped with a shading ring on one-half of the core (Photo 2).
An electrical relay is a switch that is under the control of another circuit. A classic example is the system used to start a car â when someone turns an ignition key, the ignition does not interact directly with the car battery. Instead, it activates a relay, which passes the signal on so that the car can start.